Why did my tire explode?

The last two days, I’ve been riding Sun 28 (Just got it on Monday.)

Seems to be good, the tire goes from 50-75 recommended, 85 max PSI.

I infated it to about 68 PSI.

Rode it about 5 miles or so yesterday, get home, lock it in the back of my car (where I usually keep my uni). No big change in weather or temp overnight.
I get up this morning, look in my car, and the tire’s been blown off the rim. The inner tube is ripped badly…shreds are hanging out from the rim.

The rim strip and everything is in good condition.

What would make the tube explode like that when I’m not riding it?

Hmmmm I Have No Idea. There Arent Any Spokes Pokin Thru To Where The Tube Would Be??

We’ve seen several incidents like yours. Mostly it happens to the plastic rimmed unicycles but we’ve seen some steel rim incidents as well. If the tire bead slips from the rim, the tube will force its way through the gap and explode. When mounting the tire, always ensure that the rim bead is seated properly. Usually there is a line around the perimeter of the tire that can be used to align the tire on the rim.

Your situation may be something entirely different. Let us know what you find out.


Well, I’m not likely to find out anything anymore…I bought a new tube and put it on this afternoon, and threw away the last one.

Didn’t think I’d be putting money into a new uni 2 days after getting it, but oh well.

If it happens again, I’m getting one of those solid foam airless/tubeless tires someone posted a few days ago.

I brought it to the bike shop where I got the tube and showed them…they had no idea, either.

yeah, your tyre just crept off the rim. make sure its well seated next time you pump it up.


the cheap Sun rim could not have a good enough hook on it to hold on the tyre recomended pressure.

What is a hook?
I don’t know much about cycles.

The tire has a lip where it fits onto the rim bead. Which is a lip also,only inward facing. The opposing lips form the seal that keeps the tube inside the tire. If your concerned that your tire is improperly installed. Let all of the air out of it. Pinching the tire between your thumb and forefinger. Rock the tire back and forth inside the rim then reinflate. This should help. If it doesn’t.
Your tire might not fit the rim.
The bead may still not be seated properly.
Your adding too much air pressure.
Are you using a gauge?

Jag’s talking about the way the tire bead hooks onto or under the rim bead.

read these.

I’ll tell you why because you touch yourself at night hahahahahahaha oh Family guy is the best show ever

Ah…I get it.
Cool, and thanks for the links.

My sun 28" tire blew out the 2nd day for me as well. I was inflating the tire, got to about 60 psi. Loudest noise I had heard in in 30 years. It sorta freaked me out. I’ve been cautious, gloves, safety glasses and ear protection just to put air in that tire ever since.

I did find metal splinters around the spoke nuts and shavings in the tire. Removed the splinters and replaced the rim tape before replacing the tube.

The 28" been fun ever since. Good luck with your 28".

As others have pointed out, the tire bead comes off of the rim and the tube comes out. Unrestricted by the tire, it begins to expand rapidly (and usually catastrophically). In UniVerse 2 there is a sequence with Jacinto hopping onto a rock in which this happens in a VERY LOW pressure tire so the tube doesn’t pop before it reaches equilibrium. It looks like the Monty setup which was notorious for this problem.

A good approximation is that the energy contained in a properly inflated tire is about the same as a round of .45ACP or a cherry bomb; something of the order of a kilo-joule. That’s why it sounds so loud, especially in close quarters like your basement or garage. Acoustically it’s enough to damage your ears…and soil your underwear.

Ah…I have the U2 video, and always wondered why that was happening…

I didn’t know that there was so much energy in a tire!

yes, but no where near a .45LC or a .44MAG :sunglasses:

where yoopers? oh yeah he probobly likes the .308 or the 30-06

Or .454 Casull or .50AE for that matter if we’re talking about pistol rounds. The .308 and .30-06 are high powered rifle rounds. And I said of ORDER one kilo-joule so 300 joules to 3 kilo-joules. I’ll bet the rifle rounds are in there somewhere.

Bruce would certainly go for the rifle, I think his was a .30-06 in the picture. I don’t know him to be much of a pistolero. He is undoubtedly formidable with the rifle.

I had a 700cx25 at 90 psig go off about three feet away from me in my basement. That was about 700 Joules. My ears were ringing for awhile after that.

yes, that what ment when i mentioned Yoopers…when that mans tyre blows there is much more addes joules therefor the referance not to mention the pic that i cant dig up tonite. to much 50cal sabot loading for me tonite.

Exactly the same thing happened to me.

I had just bought my 24" Nimbus the same day. I assembeled it (with some help from my father). I Rode it around a bit. I couldn´t ride very good back then, something like 5 revolutions. I leaned it to a wall beacuse it was time for dinner.
And then suddenly A very load noice is heard, like a gunshot ;). Everybody thought someone were shooting in our backyard. But then we realiced it was thu unicycles tire that had exploded! Yikes!!!

But we called unicycle.se and we got a brand new tire and a new tube the following day.

You all know me too well. :slight_smile:

You know, the other issue that needs to be noted is high pressure tires on sub-standard rims. Unicyclists will commonly inflate a tire an additional 50% or more of the rated pressure on the side of the tire. Many of the single-wall OEM steel rims can’t handle that amount of pressure. We’ve also had a couple incidents of rims giving way and causing the same explosion.